(a) Technical Field
The present invention relates to a sound absorbing and insulating material with improved heat resistance and moldability and a method for manufacturing the same, more particularly to a sound absorbing and insulating material having, as a surface layer, a heat-resistant material prepared by impregnating a binder into a nonwoven fabric formed of a heat-resistant fiber stacked on one side of a base layer formed of a conventional sound absorbing and insulating material, which has improved sound-absorbing property, flame retardancy, heat-insulating property and heat resistance as compared to the conventional sound absorbing and insulating material, is applicable to parts maintained at high temperatures of 200° C. or greater due to the surface layer and is moldable into a desired shape during the curing of the binder impregnated into the surface layer, and a method for manufacturing the same.
(b) Background Art
Noise, as an unwanted side effect of industrial development, causes gradually more damages. Accordingly, various methods have been provided to prevent noise. As a way of such noise prevention, researches for developing new sound absorbing and insulating materials capable of arresting, absorbing or insulating sound have been conducted in various ways.
Representative industrial sectors requiring sound absorbing and insulating materials include electric appliances such as an air conditioner, a refrigerator, a washing machine, a lawn mower and the like, transportation such as an automobile, a ship, an airplane and the like, construction materials such as a wall material, a flooring material and the like, and so forth. The sound absorbing and insulating material is required in other various industrial fields, too. In general, the sound absorbing and insulating materials used in industries require, in addition to good sound-absorbing property, reduced weight, flame retardancy, heat resistance and heat-insulating property, depending on their applications. Especially, flame retardancy and heat resistance may be further required for sound absorbing and insulating materials used in engines, exhaust systems and the like maintained at high temperatures of 200° C. or greater. At present, an aramid fiber is gaining attentions for sound absorbing and insulating materials having superior heat resistance.
In addition, in order to provide functionalities such as flame retardancy, water repellency and the like to a sound absorbing and insulating material, many sound absorbing materials wherein a nonwoven fabric containing aramid fibers and a functional skin material are stacked have been developed.
For example, Korean Patent Publication No. 2007-0033310 discloses a flame-retardant sound absorbing material wherein a nonwoven fabric layer in which a heat-resistant short aramid fiber and a short thermoplastic polyester fiber are bridged and a skin material layer formed of a wetlaid nonwoven fabric consisting of a short aramid fiber are stacked.
In addition, Japanese Patent Publication No. 2007-0039826 discloses a water-repellent sound absorbing material wherein a nonwoven fabric layer of a heat-resistant short aramid fiber or a blend of a short aramid fiber and a short thermoplastic polyester fiber and a skin material layer treated with a water repellent are stacked.
Further, Japanese Patent Publication No. 2007-0138953 discloses a heat-resistant sound absorbing material wherein a nonwoven fabric layer consisting of a heat-resistant aramid fiber and a skin material layer formed of a fiber sheet containing a heat-resistant aramid fiber are stacked.